Double clutch transmissions are currently increasingly used in motor vehicle construction, due to their numerous advantages. A key member of this type of transmission is the wet running or dry running double clutch, which respectively transmits engine torque to one of two partial transmissions. While one clutch is closed, the other one is opened. The gear speed is then shifted on the transmission shaft of the opened clutch. In case the opened clutch produces large drag moments in this context, these moments have to be overcome during synchronization of the gear speeds, in addition to the inertia of the transmission shafts. In practice, this means either a decrease of the service life of the synchronizing units or, usually, the use of more efficient and thus more expensive synchronizer rings. Simultaneously, the large drag moments contribute to an increased fuel consumption of the vehicle. The drag moments mainly result from the fact that both clutches have to be lubricated together during operation. Liquid friction between the clutch disks causes these moments.
It is therefore an object underlying some embodiments of the present invention to provide a double clutch of a double clutch transmission which enables a separated lubrication of its clutches, and is simultaneously structured in a space-saving coaxial or nested design with clutches disposed within one another.